Control apparatus



Feb. 10, 1942. R. L. wlLsoN CONTROL APPARATUS 5 'Sheets-Sheet 1 Original Filed June 10, 1938 Feb. 1o, 1942. R, L. WILSON Re. 22,026

CONTROL APPARATUS Original Filed June l0, 1958 y 5 Sheets-Sheet 2 f yla l? a 1 y A |||||||s I J-4'6`a Feb, 10, 1942. .Y R, WILSON Re. 22,026

CONTROL APPARATUS Original Filed June 10, 1938 5 Sheets-Sheet` 3 Feb.1o,1942. R,. W1LSON V Re. 22,026

CONTROL APPARATUS FFL?? 12931.. j

'flex/s R. L. wlLsoN CONTROL APPARATUS 5 She'ets-Sheet 5 fr/args.

Original Filed June l0, 1938` Reissued Feb. 10, 1942 22,026 CONTROL APPARATUS Rosser L. Wilson, Mahwah, N. J., assignor to The American Brake Shoe and Foundry Company, New York, N. Y., a corporation of Delaware Original No. 2,232,751, dated February 25, 1941, Serial No. 291,844, August 25, 1939, which is a division of Serial No. 213,103, June 10, 1938. Application for reissue August 5, 1941, Serial 36 Claims.

This application is a division of my-copending application, Serial No. 213,103, filed June 10, 1938.

This invention relates generally to control` apparatus, and more particularly it relates to such apparatus applied to at least two relatively movable elements to detect variation from a desired relative speed of such elements and to accomplish predetermined control Operations in response to the detection of such undesired variation. An instance of two relatively movable elements where such undesired variation in relative speed may occur is found in railway and like equipment wherein the several wheels normally rotate substantially in unison, and wherein material variation from such rotative relation is indicative of an undesired sliding action or tendency toward such an action of one of the wheels. k

In the normal operation of railway equipment it is believed that there is no slippage at the points of contact of the wheels of the equipment with the rails and that the wheels roll along the rails. During a braking operation on such equipment the retarding forces effective on the wheels react at the rails to slow down the rolling movement of the wheels and so long as the adhesion between each wheel and rail on which it rolls exceeds the retarding force effective on the wheel, the wheel is retarded without slippage at the contact thereof with the rail. It has been observed, however, where the retarding force in a braking operation exceeds the force of adhesion between a wheel and the rail on which it rolls, that the wheel slips on the rail and is thereafter retarded at a rate exceeding that at which it would have been retarded had not the slippage occurred and as a result the wheel comes to rest prematurely and thereafter slides along the rail.

There are many factors which may cause the retarding force effective on a wheel in a braking operation to exceed the adhesion between the wheel and the rail on which it rolls. For example, the braking means of railway equipment is so arranged that the friction between the elements thereof is less than what has come to be generally accepted as the usual value of the adhesion or friction between the wheel or wheels decelerated by operation of the braking means and the rail or rails on which such wheel or wheels rolls or roll. There may be, however, an' unpredictable increase in the friction between the elements of the braking means or the friction between the wheel or wheels and rail or rails may unaccountably drop below what has come to be generally accepted as the value of such friction, and of course there may be a combination of such variations. If such variation occurs in a braking operation it is quite likely that the wheel or wheels affected thereby will slip on, rather than roll on, the rail or rails whereupon, as previously explained, the wheel or wheels may prematurely stop rolling and thereafter slide along the rail or rails. Such sliding of the wheels along the rails may impair the braking operation in which it occurs and may result in serious damage such as pro- Y ducing sO-called ats on the wheels. It will be understood that wheel sliding may be occasioned in a wide variety of ways but that however occasioned itis objectionable.

It has been observed in braking operations on railway equipment that, when a wheel slips on the rail on which it normally rolls and prematurely stops rolling and thereupon slides along the rail, the wheel, in so far as its rotative movement is concerned, decelerates rapidly after the slippage occurs and quickly stops rolling to thereupon start to slide and also that Where several wheels on different axles substantially simultaneously or simultaneously slip 'on the rail or rails on which they normally roll the wheels usually decelerate, in so far as rotative movement thereof is concerned, at different rates and ,consequently stop rolling and start to yslide at different times. Such lack of uniformity in the slowing down of the wheels is probably due to variations in the conditions at the various wheels. These variations in the conditions may be due to dilerences in the loads on the various wheels on different axles, differences in the retarding forces affecting the respective wheels on different axles, or the like. In any event, however, where several wheels on diierent axles slip on the rail or rails, a variation in the rates of rotation of the various wheels usually arises before any wheel prematurely stops rolling and starts to slide along a rail.

An important object of the present invention is to detect undesired variation in the relative speed of two or more such relatively movable objects and, in response to such detection, to initiate a control operation such as an operation adapted to restore the desired speed relation.

It is recognized that the rates `of movement of the various movable elements, such as the rates of rotation of the various wheels on a railway car or the like that are decelerated by independent braking means may not always be the same. For example, as applied to railway equipment, there maybe a difference in the diameters of such wheels at the lines of contact thereof with the rail or rails which will of course cause the wheels to rotate at different rates in normal operation as Well as during a braking operation. Thus elements operated at rates proportionate to the rates or rotation of wheels that are decelerated by independent braking means may not always operate at the same rate either in normal operation or during a braking operation. Where such elements are employed to eifect a control operation, such as the release of the braking means when the elements operate at different rates during a braking operation, there may be instances where the elements will be operating at different rates even during a braking operation and yet there will be no need of effecting the control operation because there will not be present an abnormal condition which the control operation is to overcome.

Hence still another object of the present invention is to provide such an apparatus which .l

operates only when the variation in the relative speeds of movement of the several elements exceeds a range predetermined to be indicative l of an abnormal or undesired condition.

Since in many instances, as in the case of railway equipment, elements operated at rates proportionate to the rates of rotation of wheels as aforesaid may operate at different rates, as in the course of a braking operation, under conditions in which it will not be desirable to effect a control operation, such as the selective releasing of the independent braking means operative to decelerate the respective wheels or sets thereof, it is advantageous to interpose devices entailing a time factor in their operation intermediate the elements and the means under control thereof so that a time factor will enter into the determination of the existence of an abnormal condition and so to do constitutes still another object of the present invention.

More specifically, an object of this invention is to bring about successive or alternate periods of operation of sloW-to-release relays and when the intervals between such period of operation are reduced in a predetermined amount to effectsimultaneous operation instead of alternate operation, and an object ancillary to the foregoing is to render operative means under control of the relays only upon simultaneous operation of such slow-to-release relays.

Further objects are to employ elements, such as may be operated at rates proportionate to the rates of rotation of the wheels of railway or like equipment that are decelerated by independent braking means, to alternately render operative devices which may be brought into simultaneous operation and thereby bring about a control operation or the like. and to maintain operative for a predetermined time whatever means are rendered effective to bring about the control operation whenever the interval intermediate alternate periods of operation of alternately operable devices is so reduced that the intermediate interval is eliminated; and to effect concurrent operation of normally alternately operable devices to bring about a control operation or the like and to maintain operative for a predetermined time whatever means are effective to bring about the control operation only under predetermined conditions.

In an arrangement where devices are alternately set in operation in such a way that under predetermined conditions the interval between the alternate opera-tions is so reduced that the operations become simultaneous rather than alternate, it will be recognized that there will be instances where such simultaneous operation may be relatively brief. If such an arrangement is utilized to eiect a control operation, such as the release of the braking means employed to decelerate a particular wheel or set of wheels of railway equipment, conditions might arise where the aforesaid relatively brief simultaneous operations in rather rapid succession might be caused to repeatedly occur for relatively short periods, and this would cause the control or other operation brought about by such simultaneous operations to be initiated and interrupted, successively, as where the control operation is the release of the braking means for railway equipment operative to.slow down a particular wheel or set thereof, it might bring about alternate release and application of such braking means in rather rapid succession. Furthermore, conditions might arise where the aforesaid simultaneous operation might be brief but should nevertheless effect a relatively prolonged control operation such as relatively prolonged release of the braking means.

Hence, still another object of the present invention is to associate with alternately operable devices, which may be brought into simultaneous operation, an arrangement whereby the simultaneous operation of the devices Will be caused to effect a predetermined operation even though the simultaneous operation may be relatively brief, and an object ancillary to the foregoing is to employ timed apparatus in association with alternately operable devices that may be brought into simultaneous operations so that upon simultaneous operation of the devices a predetermined operation may be effected for at least a predetermined time even though a period of simultaneous operation of the normally alternately operative devices may be relatively brief.

In many instances the performance of a control operation tends to reduce the safety factor normally present in the equipment to vwhich it is applied, as in the case of railway equipment where the control operation releases or reduces the effectiveness of the braking means as aforesaid, and in instances of this character it is an object of the invention to provide a detecting and controlling apparatus wherein the control operation is limited to a definite period of time.

-A further object is to provide a detecting and controlling apparatus of this character which may be rendered inoperative manually at any time s0 as to return the equipment with which it is associated to its normal effectiveness.

While in the foregoing discussion and in the following detailed description I refer to controlling the braking means of railway equipment, it is to be understood that my invention is not limited to control of the braking means of railway equipment for it can be employed to control braking means of other equipment on which slippage of a wheel thereof on the surface on which it normally rolls may occur, and furthermore the fundamentals underlying this invention may be employed to control a wide variety oi operations in addition to braking operations. While the invention will be described herein with particular reference to railway equipment, it is capable of still wider application; and may be conveniently and advantageously employed, for example, to maintain a timed relation in the operation of screw propellers` on ships, propeller shafts in aircraft applications, machine tool spindles, electrical generator sets, motors used in photographic transmission, conveyor feeds, and in numerous other instances where moving parts of machinery are correlated. It is therefore to be understood that the foregoing discussion and following detailed description pertain to preferred embodiments of my invention and hence such discussion and description are not tobe taken as a limitation of the invention.

Selected embodiments of my novel invention are illustrated in the accompanying drawings wherein Fig. 1 is a diagrammatic View of one embodiment of my invention associated'with a pair of wheels such as are provided at one side of a truck on railway equipment;

Fig. 2 is a Vertical sectional View of a switching means employed in the embodiment of my invention illustrated in Fig. 1;

Fig. 3 is a transverse sectional view taken substantially on the line 3-3 on Fig. 2;

Fig. 4 is a sectional detail view taken substantially on the line 4--4 on Fig. 2;

Fig. 5 is a view, similar to Fig. 1, showing another form of my invention;

Fig. 6 is a diagrammatic view of a modification of the form of the invention shown in Fig. 5;

Fig. 7 is a diagrammatic view of a still further modiiied form of the invention shown in Fig. 5S

Figs. 8 and 9 are diagrammatic views of other forms of my invention;

Fig. 10 is a diagrammatic View, partly in elevation and partly in section, of a modified form of switch that may be employed;

Figs. 11, l2 and 13 are still further diagrammatic views of still other forms of my'invention;

Fig. 13A is a diagrammatic view of still another form of switch that may he employed;

Fig. 14 is a diagrammatic view of an arrangement providing a common control for a plurality In the embodiment of my invention shown in Figs. 1 to 4, there is a switch S which includes a pair of rotors I5 and I6 respectively fast to shafts I1 and I8 journaled in suitable bearings i in the switch housing I9 A gear 26 fast on the shaft I1 meshes with a gear 2| fast on the shaft 22 which is also journaled in suitable bearings in the housing I9, the gears 26 and 2| having a one-to-one ratio. The shaft 22 extends exteriorly o-f the housing I9 and one end of a exible shaft 23 is connected to this end of this shaft, the other end of the exible shaft being connected to a gear 24 that meshes with a gear 25 connected to a movable element such as the wheel FW for rotation therewith. In the present instance the gears 24 and 25 have a one-to-one ratio but this ratio may be varied as desired. Furthermore, the flexible shaft 23 could be connected to the wheel to derive motion therefrom in other ways, if so desired, as by being directly connected to the axle to which the wheel might be fast. TheI shaft I8 also extends exteriorly of the housing and one end of a flexible shaft 26 is connected to this end of this shaft, the other end of this flexible shaft being connected to a gear 21 that meshes with a gear 28 connected to a sec`ond relatively movable element such as the wheel RW for rotation therewith, this connection of the shaft I8 to the wheel RW being similar to connection of the shaft I1 to the wheel FW.

The wheels RW and FW as illustrated are to be mounted at one side of a truck (not shown) of railway equipment for movement along the rail T. These wheels are adapted to be slowed down by the usual brake apparatus (not shown) provided on railway equipment, which apparatus includes the brake cylinder C to which a fluid under pressure may be supplied through the pipe' P. The brake apparatus is not illustrated inas much as the particular construction thereof forms no part of my invention which, in the illustrated forms, pertains to controlling the brake apparatus rather than to such apparatus per se. The relation of my invention to the brake apparatus is apparent from the illustration of my novel control means in association with the brake cylinder C to which fluid under pressure is supplied when the wheels FW and RW are to he slowed down. y

In the present instance my novel apparatus is employed to control operation of a solenoidoperated check valve 29 and a solenoid-operated vent valve 36, each of which valves is positioned in the pipe P.

A conductor 32 connects one end of the winding 3| of the solenoid of the valve 29 to one end of the winding 33 of the solenoid of the valve 36. Another conductor 34 leads from the other end of the winding 3| to a source of current such as the battery B. Still another conductor 35 leads from this source of current to a contact 36 of the slow-tO-release relay SRI, said contact 36 being engaged by the armature 31 of this relay during operation of the relay. A further conductor 38 leads from the armature 31 to a contact 39 of the slow-torelease relay SR2, this contact 39 being engaged hy the armature 46 of the relay SR2 during operation of this relay. Yet another conductor 4I leads from the armature 46 to the end of the winding 33 opposite that to which the conductor 32 is connected. Hence, the windings 3| and 33, the armatures 31 and 46, and the contacts 36 and 39 are connected in series so that energization of the windings 3| and 33 is effected, to thereby operate the valves 29 and 36, only when both the armatures 31 and 46 are engaging the contacts 36 and 39, this occurring only when the relays SRI and SR2 are operative simultaneously.

A conductor 42 leads from a source of current such as the battery BI to a terminal 43. Another conductor 44 leads from the terminal 43 to one end of the winding 45 of the relay SR2 and a conductor 46 leads from the terminal 43 to one end of the winding 41 of the relay SRI. Still another conductor 48 leads from the source of current BI to a terminal 49, Fig. 2, in the switch S. A further conductor 56 leads from the end of the winding 41 opposite that to which the conductor` 46 is connected toa terminal 5I in the switch S. Yet another conductor 52 leads from the end of the winding 45 opposite that to which the conductor 44 is connected to a terminal 53 in the switch S.

A conductor ring 54 is mounted on the rotor I6 and a pair of conductor rings 55 and 56 are mounted in spaced relation on the rotor I5. The rotors I5 and I6 are preferably made of insulating material and hence the conductor` rings 55 and 56 are insulated one from the other. A spring contact 51 mounted on the terminal 49 bears on the conductor ring 54 while spring contacts 58 and 59, respectively mounted on the terminals 5I and 53, respectively bear on the conductor rin-gs 56 and 55. A pair of contact strips 60 and 6I are mounted in the periphery of the rotor I5 in diagrammatically opposite positions. These strips (see Fig. 3) each preferably extend over one-quarter of the periphery of the rotor so that the spacing between adjacent ends thereof is ninety degrees and the extent of each strip over the periphery of the rotor is ninety degrees. A conductor G2 (Fig. 4) interconnects the contact strip 60 with the conductor ring 56 while a conductor 63 .connects the contact strip 6I with the conductor ring 55. A spring finger 64 is mounted in the rotor I6 in electrical connection with the conductor ring 54 and extends over that part of the periphery of the rotor I5 on which the contact strips 60 and 6I are provided so that if the rotors I5 and I6 move relative to each other the spring nnger 64 alternatively engages the contact strips 60 and 6|. Thus, these contact strips serve as a commutator while the spring finger 64 serves as a brush.

When the spring nger or brush 64 engages the contact strip 60, circuit is established from the source of current BI through conductor 48, spring contact 51, conductor ring 54, brush 64, contact strip 6D, conductor 62, conductor ring 56, spring contact 58, conductor 5I), through winding 41 and conductors 46 and 42 back to the source of current BI whereupon the slow-to-release relaySRI is energized. When, however, brush 64 engages the contact strip 6I circuit is established from the source of current BI through conductor 46, spring contact 51, conductor ring 54, brush 64, contact strip 6l, conductor 63, conductor ring 55, spring contact 59, conductor 52, through winding 45 back to the source of current BI through con-` ductors 44 and 42 whereupon the slow-to-release relay SR2 is energized.

It will be noted that the rotor I5 is connected through shaft I1, gears and 2l, shaft 22, flexible shaft 23 and gears 24 and 25 to the wheel FW to rotate therewith and in the same direction and also that the rotor I6 is connected through shaft I8, flexible shaft 26 and gears 21 and 28 to the wheel RW to rotate therewith and in the same direction. Hence when the Wheels FW and RW are rotating the rotors I5 and I6 rotate at rates proportionate to the rates of rotation of the respective wheels, and in the present instance, by reason of the one-to-one ratio between the gears of the various sets thereof, the rotors rotate at the same speed as the wheel to which each is respectively connected. It will be recognized, however, that the rotors could be caused to rotate at greater or less speeds or rates than the wheels, it only being important that the rates of rotation of the rotors be proportionate to the rates of rotation of the wheels.

When the rotors I5 and I6 both rotate at the same rate there is no relative movement therebetween and the brush G4 rests on one or the other of the contact strips 60 and 6I or in a space between adjacent ends of these strips, such spaces being of sufficient width and the brush being sufficiently narrow that the brush cannot engage both Contact strips at the .same time. Of course, whenever the brush 64 engages one or the other of the contact strips 66 or 6I, either the slowto-release relay SRI or the slow-to-release relay SR2 is energized.

In the normal operation or railway equipment it is believed that there is no slippage at the points of contact of the wheels with the rails and the wheels roll along the rails. During a braking operation effective on the wheels of such equipment the retarding forces react at the rails to slow down the rolling movement of the wheels and so long as the adhesion between each wheel and the rail on which it rolls exceeds the retarding force effective on the wheel, the wheel is retarded without slippage at the contact thereof with the rail. However, when the retarding force in =a braking operation exceeds the adhesion be tween a wheel and the rail on which it normally rolls, the wheel slips on the rail and is thereafter retarded at a rate exceeding that at which it would have been retarded had not the slippage occurred, and as a result the wheel comes to rest prematurely and thereafter slides along the rail.

Thus, where either the rotor I5 or I6 is connected to a wheel which is retarded in the manner just described and the other rotor is connected to a wheel which continues to roll on the rail, it is apparent that the rotor connected to the wheel which is so retarded will move relative to the other rotor in relatively rapid manner whereupon the contacts or brush 64 will engage the contact strips 60 and 5I in rapid succession. The rapidity with which the brush 64 so successively engages the contact strips 60 and 6I is directly proportionate to the magnitude of the diierence in the rates of rotation of the wheels. The magnitude of such difference is relatively great when only one of the wheels slips on the rail while the other continues to roll on the rail. However, it has been observed, where several wheels slip on the rails at the same time, that the wheels do not slow down uniformly, this probably being due to varying conditions at the several wheels. Hence, Where both the Wheels to which the rotors I5 and I6 are respectively connected slip on the rail, it is very unlikely that they will slow down uniformly and hence even in this condition there will be relative movement between the rotors I5 and I6 and the brush j64 will successively engage the cont-act strips 66 and 6I.

As explained heretofore, the contact strips 60 and 6I and the contacts or brush 64 are so arranged in circuit with the slow-to-release relays SRI and SR2 that when the brush 64 engages the Contact strip or conductor segment 6U the relay SRI is energized, and when the brush 64 engages the strip 6I the relay SR2 is energized. Each of these relays is maintained energized so long as the brush E4 remains in engagement with the contact strip in circuit with the particular relay and when, for example, the relay SRI is energized it attracts its armature 31 which thereupon engages the contact 36. Likewise when relay SRZ is energized it attracts its armature 40 which thereupon engages the Contact 39. Furthermore, each of these relays, being a slow-torelease relay, remains operative after circuit thereto is broken, that is to Say, for a predetermined time aiter circuit to the relay is broken its armature remains in engagement with the contact engaged by the armature vupon energization of the relay, this being an inherent characteristic of a slow-to-release relay.

Hence, when the brush E4 successively engages the contact strips 60 and 6I in such a way that one contact strip is disengaged and the other strip is engaged and the relay in circuit with the second of the strips so engaged is energizedk in a period of time less than the predetermined time, the relay in circuit with the first of said strips remains operative after circuit thereto is broken,

by disengagement of the brush 64 from the contact strip in circuit therewith, then both the relays SRI and SR2 are simultaneously operative. When this Occurs both the armatures 40 and 31 are engaged with their cooperating contacts 39 and 36 and circuit is closed through the windings 3| and 33 whereupon a control operation, such as release of the braking means effecting retardation or slowing down of the wheels, is effected, as will be more fully explained presently.

It is recognized that by reason of conditions encountered in the actual use of railway equip-` ment there will be differences in the rates of rotation of wheels even when all the wheels are normally rolling along the rails. Such differences in rates of rotation may be due to differences in the diameters of the wheels at the lines of contact thereof with the rails. In fact there may be variations in the diameter of a single wheel at the line of contact thereof with the rail as the wheel rolls along the rail due to move- `ment of the wheel in an axial direction. Since such conditions will exist, it is apparent that all diiferences in rates of rotation between wheels, to which rotors as I5` and I6 are respectively connected, should not cause these rotors to so rotate relative to each other that a control operation will be brought about. A control operation is not required unless an abnormal condition exists. To avoid a control operation unless an abnormal condition exists, provision is made to r,care for an extreme condition in actual operation, that is, a condition quite unlikely to be encountered, and the apparatus is so arranged that a control operation will not be effected under such extreme condition. In selecting such an extreme condition, one is chosen that will bracket other similar conditions and improper or undesired effecting of a control operation is therefore avoided.

An example of such an extreme condition is where railway equipment is operating at a speed of one hundred twenty miles per hour and the difference in diameters of the wheels to which the rotors I5 and I6 are connected is'one inch` at the lines of contact of such wheels` with the rail or rails on which they normally roll as, for example, where the diameter of one wheel at the line of contact thereof with the rail is thirty-two inches and the diameter of the other wheel at the line of contact thereof with the rail is thirtythree inches. If a condition such` as this prevailed the rotors I5 and I6 would rotate relative to each other even in normal operation and in the absence of slippage on the rail for there would be a difference in rotation therebetween of .634 revolution per second.

As explained above, each of the contact strips 60 and El extends over one-fourth of the diameter of the rotor I5 so that there is a ninety degree interval intermediate adjacent ends of the strips as well as a ninety degree extent of the strips. Thus, under the foregoing conditions where there is a difference of .634 revolution per second inthe rotation of the rotors I5 and I6 it will require .394 second for the brush 64 to travel from the end of one contact strip 60 or 6I to the adjacent end of the other contact strip. Hence if the slow-to-release relays are timed to remain operative, after circuit thereto is broken, for less than .394 second, the armatures 31 and 44 will not be simultaneously engaged with their cooperating contacts 36 and 39 under the extreme condition mentioned above which is an operating speed of one hundred twenty `miles per hour and a difference in the diameters of the wheels at the lines ofcontact with the rail of one inch.

It is, however, advantageous to afford a safety factor. Hence the slow-to-release relays may be timed to remain operative after circuit thereto is broken for approximately .242 second. In this circumstance, in order for the armatures 31 and 40 to be simultaneously engaged with their cooperating contacts it is necessary for there to be such relative rotation between the rotors I5 and I6 that the brush 64 will move from engagement with one of the contact strips 6U or 6I into engagement with the other of the contact strips in .242 second or less. It will be apparent that this is well beyond the time required for such successive engagement in the extreme condition described above which means that a control operation will not be brought about under normal operating conditions.

However, where slippage occurs between a wheel, to which one of the rotors I5 or I6 is connected, and the rail on which the wheel rolls, and the other wheel does not slip, or even if there is slippage between both wheels to which the rotors are respectively connected, and the rail or rails on which such wheels normally roll, there will be appreciable relative rotationV between the rotors I5 and I5. Furthermore, once a wheel slips on the rail it thereafter, so far as its rotative movement is concerned, slows down rapidly and therefore almost or actually simultaneously with wheel slippage relative rotation between the rotors l5 and I6 is set up. Hence as soon as slippage occurs the brush 64 starts moving rapidly from engagement with one. contact strip 60 or 6I into engagement with the other of the contact strips. Moreover, as soon as the time required for the brush 64 to move from one conta-ct strip to the other is equal to or less than .242 second, both the armatures 31 and 40 will be engaged with their cooperating contacts 36 and E39 whereupon circuit will be closed to the windings 3I' and 33 to effect a control operation. Since slippage causes relatively great relative rotation between the rotors i5 and I6, the brush 64 will move from one contact strip to the other in .242,second or less practically simultaneously with the initiation of wheel slippage.

While it is necessary that simultaneouse engagement of the armatures 31 and 40 with their cooperating contacts is to be avoided in normal operation, it is desirable to establish this simultaneous cooperation promptly under abnormal conditions, as when slippage occurs, and to illustrate the` promptitude with which this would be brought about under abnormal conditions it is possible to effect simultaneous closing of the switches, of which the armatures 31 and 40 are a part, by only having slightly more than ninety degrees of relative rotation between the rotors I'5 and IG for the brush 64 may be near the end of one contact strip at the time rapid relative rotation between the rotors I5 and I6 is'initiated and thus the brush need only move slightly more than ninety degrees to engage the other contact strip and effect simultaneous closing of the switches. It will be recognized that such movement may be effected very rapidly and from this it will be seen that the device is quite sensitive to abnormal differences in the rates of rotation between wheels as FW and RW.

To further explain the simultaneous closing of the switches, of which the armatures 31 and 40 are a part, when an abnormal condition arises as, for example, in event of Wheel slippage in the course of a braking operation, if the relays SRI and SR2 have a release time of approximately .242 second and the diameter of both the wheels FW and RW at the lines of contact thereof with the rails is approximately thirty-three inches, (in this circumstance there will be no relative rotation between the rotors I5 and I6 in normal operation) a difference in the rates of rotation of the wheels equivalent to approximately six miles per hour will cause the brush 64 to move from association with one contact strip 6D or 6I into engagement with the other contact strip in approximatelyl .242 second and in proportionately less time as the difference in the rates of rotation increases.

Since it is probable that the rotors I5 and I6 will be rotating relative to each other even in normalv operation, a further example of the operation of my novel apparatus, with particular reference to the extreme condition explained above, is now set forth. In such an extreme condition, entailing the connection of the rotors I5 and I6 respectively to wheels having an inch difference in diameter, that is, where one wheel is approximately thirty-two inches in diameter at the line of contact thereof with the rail and the other wheel is approximately thirty-three inches in diameter at the line of contact thereof with the rail, there will normally be, in the absence of wheel slippage on the rail, a difference of approximately .634 revolution per second in the rates of rotation of the wheels at one hundred twenty miles per hour. This is equivalent to a speed of approximately three and three-quarters miles per hour at the circumference of a thirtythree inch wheel. Now if, in such circumstances, the smaller wheel slips on the rail so as to alter the normal difference in the rates of rotation of the wheels, a difference in the rates of rotation between the wheels equivalent to approximately a speed of nine and three-quarters miles per hour at the circumference of a thirty-three inch Wheel will cause the brush 64 to move from engagement with one contact strip 6I] or 6I into engagement with the other contact strip in approximately .242 second and in proportionately less time as the difference in rates of rotation increases.

From the foregoing it will be apparent that wherever the difference in the rates of rotation between wheels as FW and RWv is such that the brush 64 moves from engagement with one contact strip 66 or 6I into engagement with the other strip in less than .242 second, when the relays SRI and SR2 have a release time of .242 second, then a control operation is initiated. In the present instance the control operation entails energization of the windings 3| and 33 with the result that the check valve 2S is cio-sed and the vent valve is opened. In the course of a braking operation fiuid under pressureis supplied through the pipe P to the cylinder C so long as the check valve 29 is open. Thus when in the course of a braking operation the check valve 29 is closed and vent valve 30 is opened the cylinder C is disconnected from the source of uid under pressure by the closing of the valve 29 and is vented to` the atmosphere, in the present instance, by the opening of the valve 3i), this venting resulting in reduction of pressure in the cylinder and effecting release of the braking means. Of course the arrangement could be such as to reduce the effectiveness of the braking means, rather than release thereof, if this were desired.

As soon as the braking means are released or reduced in effectiveness the retarding force effestive on the wheels is removed or reduced, as the case may be, and thereupon the wheels tend to resume normal rolling along the rails. When the wheels resume normal rolling along the rails the difference in the rates of rotation therebetween become such that the brush 64 no longer moves from engagement with one of the contact strips 60 or 6I into engagement with the other of the contact strips in .242 second or less and therefore the switches of which the armatures 31 and dii are a part do not remain closed with the result that circuit to the windings 3| and 33 is broken and thereupon the vent Valve 3U closes and the check valve 28 opens. If the means operative to bring about the braking operation are still operating when this occurs, the braking means are again rendered eifective and if the retarding forces do not again bring about a difference in the rates of rotation of the Wheels there will not be such movement of the brush 64 from engagement with one contact strip 60 or 6I into engagement with the other contact strip that the windings 3l and 33 will be energized. If, however, re-application of the braking means again sets up a difference in the rates ofv rotation between the wheels as FW and RW such that the brush 64 moves from engagement with one of the Vcontact strips 60 or 6I into .engagement with the other strip in .242 second or less, the above described operation will be repeated.

It will be appa-rent from the foregoing that, since the slow-to-release relays SRI and SR2 are simultaneously rendered operative by reason of a difference in the rates of rotation of wheels as FW and RW, a control operation can be initiated prior to the time one of the wheels prematurely stops rolling and therefore, where the control operation results in the release of the braking means, sliding of a wheel along a rail may be avoided. for when the braking means are released (or reduced in effectiveness) the wheels, being freed of a retarding force, resume normal rolling along the rail.

In the form of my invention illustrated in Fig. 1 there may be such difference in the rates of rotation of wheels as FW and RW that rthe brush 613 will move from engagement with one contact strip 66 or 6I into engagement with the other contact strip in or less than .242 second to thereby render the relays SRI and SR2 operative simultaneously but the difference in the rates of rotation may be such that the brush 64 will not be freed from the second of the contact strips so engaged and move back into engagement with the first of the contact strips so engaged in .242 second. In such an instance the first of the relays SRI or SR2 to be energized might release prior to the time the brush engaged the contact strip in circuit with this particular relay and if this occurred circuit to the windings 3| and 33 would be broken. In a circumstance such as this a condition might arise where the difference in the rates of rotation of the rotors I5 and I6 would be such that the relays SRI and SR2 might be rendered operative simultaneously as the brush moved from engagement with one of the contact strips 66 or 6I into engagement with the other of the Contact strips but such simultaneous operativeness of the relays would not be maintained until the brush moved from the second of the strips so engaged back into engagementwith the rst of the strips so engaged. It will be apparent that if conditions such as this arose circuit would be alternately closed and opened through the windings 3| and 33 with the result that the valves 29 and 30 would both be rendered operative and then inoperative, alternately, which is to say, a control operation would be alternately initiated and interrupted.

In order to avoid such alternate initiation and interruption of a control operation my novel apparatus may be arranged in the manner illustrated in Fig. 5 wherein rotors similar to the rotors I5 and I6 in a switch Sa are respectively connected to wheels FWa and RWa through ilexible shafts 23a and 26a, the switch S'a and the flexible shafts 23a and 26a being similar to the switch S and the exible shafts 23 and 26 and being adapted for operation in a similar manner. Furthermore, slow-to-release relays SRla and SRZa, similar to relays SRI and SR2, are provided as well as a source of current as the battery Bla.

In this instance a conductor 42a leads from the source of current Bla to a terminal 43a and a conductor Ma leads from the terminal 43a to one end of the winding 45a of the slow-to-release relay SRZa. Another conductor 46a leads from the terminal 43a to one end of the winding 41a of the slow-to-release relay SRla.

As in the case of the switch s, a brush in the switch Sa, corresponding to the brush 64, is connected to the source of current Bla through a conductor 48a while a contact strip in the switch Sa, corresponding to the contact strip 60 is connected to a conductor 50a which leads to the end of the winding 41a opposite to that to which the conductor 46a is connected. Further, a contact strip in the switch Sa, corresponding to the contact strip 6l is connected to a conductor 52a which leads to the end of the winding 45a opposite that to which the conductor 44a is connected. (The switches shown in conductors 50a and 52a are explained hereinafter and for the purpose of the present description should be considered as being closed.

Slow-to-release relay SR2a includes an armature 40a and a contact 39a and the slow-to-release relay SRla includes an armature 31a and a contact 36a. A conductor 66 interconnects a contact 39a and the armature 31a. The armature 40a is grounded as indicated at 4la.

In the form of the invention shown in Fig. 5 a third slow-to-release relay SRS is provided which includes a winding 61, one end of which is connected to a source of current as the battery B2 through a conductor 6B', said source of current being grounded at 69.` The other end of said winding 61 is connected to the contact 36a through aconductor 10. The relay SR3 includes an armature 1l that is grounded as indicatedat 12 and this relay also includes a contact 13 engageable by the armature 1l upon energization of the relay SR3. A solenoid 14 is provided to control operation of the combined check and vent valve 15: provided in the pipe Pa through which fluid under pressure is supplied to the brake cylinder Ca which corresponds to the brake cylinder C. Upon energization of the solenoid 14 the valve 15 is operated to shut off supply of fluid under pressure to the brake cylinder Ca and to vent said cylinder, the valve 15 therefore performing the function of the valves 2,9 and 30 shown in Fig. 1.

The solenoid 14 includes a winding 16, one end of which is connected through a conductor 11 to a source of current such as the battery B3 that is grounded as indicated at 18. A conductor 19 interconnects the other endof the winding 16 to the contact 13.

In the form of the invention shown in Fig. 5 when a brush in the switch'Sa, corresponding to the brush 64, rests on a contact strip in the switch Sa, corresponding to the contact strip 6U, circuit is closed from the source of current Bla through conductor 48a and through the switch Sa, in the manner described in the description of the switchS, to a conductor Ella and through winding 41a and conductors 46a and 42a backto the source of current Bla whereupon the slowto-release relay SRla is energized. When, however, a brush in the switch Sa, corresponding to the brush 64, engages a contact strip in the switch Sa, corresponding to the contact strip 6I, circuit is closed from the source of current Bla through conductor 48a and through the switch Sa, in the manner described, to conductor 52a and through the winding 45a and conductors 44a and 42a back to the source of current Bla whereupon the slow-to-release relay SRZa is energized.

Energization of the relay SRla attracts the armature 31a thereof which thereupon engages the contact 36a, this armature remaining in engagement with this contact after circuit to the winding 41a is broken for a predetermined time inasmuch as the relay SRla is a slow-to-release relay. Thus the armature 31a engages the contact 36a so long as the relay SRla is operative. Likewise encrgization of theslow-to-release relay SR2a attracts the armature 40a which thereupon engages the contact 39a, and this armature 40a remains in engagement with this con-- tact after circuit to` the winding 45a is broken for a predetermined period of time inasmuch as the relay SRZa is a slow-to-release relay. Hence the armature 40a remains in engagement with the contact 39a so long as the relay SRZa is operative.

It will be noted that engagement of the armature 31a. with the contact 36a in the absence of the engagement of the armature lllla with the contact 39a does not close circuit from ground 4la through armature 43a, contact 39a, conductor 66, armature 31a, contact 36a, conductor 10, winding 61, conductor 68, battery B2 to ground 69 to effect energization of the slow-torelease relay SR3. Furthermore, the engagement of the contact 40a with the contact 39a in the absence of the engagement of the armature 31a with the contact 36a likewise does not close the just described circuit to effect energization of the slow-to-release relay SR3.

When, however, a brush in the switch Sa, corresponding to the brush'64, moves from engagement with one of the contact strips in the switch Sa, corresponding to the contact strips and Sl, and engages the other contact strip during the time the slow-to-release relay energized by the engagement of said brush with the rst of said Contact strips still have the armature thereof engaged with the cooperating contact and the relay energized by engagement of said brush with the second of the contact strips has attracted its armature into engagement with its cooperating contact, then the armature 46a will be engaging the contact 39a and the armature 31a will be engaging the contact 36a wherefore circuit to the winding S1 is closed and thereupon slow-to-release relay SH3 energizes.

The slow-to-release relay SR3 has a release time suiiiciently prolonged that whenever this relay is energized it remains operative for a period sufficient to insure a control operation of not less than a predetermined period of time. rThus where, as in the present instance, the slowto-release relay SRS is arranged to control the supply of fluid under pressure to a brake cylinder as Ca, energization of this slow-to-release relay will initiate release of the braking means of which the cylinder Ca is a part (or will reduce the effectiveness of such braking means) and will maintain this braking means released (or reduced in effectiveness) for not less than a predetermined period of time irrespective of how long the armatures 31a and 40a. remain in engagement with their co-operating contacts, this being due to the fact that energization of the slow-to-release relay SR3 initiates an operation which is not interrupted until release of the slow-to-release relay SR3. If the circuit is closed to the winding 51 of the relay SR3 for but a short time the operation under control of the relay SR3 will proceed for a period of time equal to the time of relatively brief energization of the winding 61 plus release time of the relay SH3, and since the energization will be relatively brief the control operation will proceed for substantially the period of time represented by the release time of the relay SRS. In any event, however, the control operation will proceed for a period of time equal to the period for which the winding 61 is energized plus the release time of the relay SR3.

Therefore by providing the relay SR3 with a release time sufficiently prolonged that a control operation of not less than a predetermined period will proceed each time the relay SR3 is energized it is possible to avoid objectionable alternate initiation and interruption of a control operation such as might result from the utilization of an arrangement such as shown in Fig. 1. Thus where the control operation is the release (or reduction in effectiveness) of the braking means of railway equipment, objectionable alternate release and application of the braking means will be avoided. Of course, even in this arrangement alternate release and application of the braking means might occur under a condition where the winding 61 was only momentarily energized and where, at the expiration of the release time of the relay SR3, both the armatures 31a and 48a would not be engaging their cooperating contacts, but wherein such engagement of the armatures would be effected shortly after release of the relay SRS which would again result in energization of the relay SRS and which would of course bring about another release of the braking means.

Release of the braking means by the arrangement illustrated in Fig. is effected whenever the relay SR3 is operative for when this relay is operative the armature 1| thereof is engaged with the contact 13 vwhereupon circuit is closed from the ground at 12, through armature 1l, contact 13, conductor 19, winding 18, conductor 11, battery B3 to ground at 18, which energizes the solenoid 14 and operates the valve 15 to close off the supply of fluid under pressure to the brake cylinder Ca and vent this cylinder to the atmosphere.

It has been explained heretofore that there may be relative movement between rotors as I5 and I6 even in normal operation of railway equipment and it has also been explained that whenever a brush such as the brush 64 is in engagement with a contact strip as the contact strips 6U and 6I the slow-to-release relay in circuit with the contact strip so engaged by the brush will be energized. However, where my novel apparatus is employed to prevent wheel sliding in the course of a braking operation by either releasing the braking means operative during such a braking operation or reducing the retarding forces established by operation of the braking means, the device may be arranged to prevent energization of the slow-to-release relays except during a braking operation by providing a control device such as the switch 80, Fig. 5. In the present instance the switch 88 is pressure-responsive and is connected to the pipe Pa. through a pipe 8l ahead of the valve 15 so that so long as there is fluid under pressure in the pipe Pa (which condition will prevail so long as a braking operation is in progress) the switch will be Closed. The switch 8U, as shown, may be conveniently arranged in the conductors 58a and 52a to thereb-y disconnect spring contacts as 58 and 59 from relays as SRIa and SRZa so long as the switch 8D was opened, which condition would prevail until fluid under pressure was supplied through the pipe Pa to the brake cylinder Ca during a braking operation. Hence, the relays as SRIa and SR2a could only be energized when a braking operation was in progress which, in the present arrangement, is the only time such relays need be energized.

There might also be conditions where it would be desirable to interrupt relative rotation between rotors. as I5 and I6, except when these rotors were to be utilized to effect a control operation, as where the control operation brought about by Vpredetermined operation of the rotors I5 and IB relative to each other is the release of braking means or the reduction of the retarding force established by operation of such means, the rotors would be rendered operative only when a braking operation is in progress. To this end a fluid-responsive clutch 82 would be interposed between the flexible shaft as 23a and a shaft corresponding to the shaft 22, and another uidresponsive clutch 83 would be interposed between the flexible shaft as 26a and the shaft as I8. A pipe as 84 connected to the pipe Pa ahead of the valve 15 leads to the clutch 82 through a branch pipe 85 and to the clutch 83 through a branch pipe 86 so that whenever fluid under pressure is supplied to the brake cylinder as Ca through a pipe as Pa. the clutches 82 and 83 are engaged to thereby connect a rotor as l5 with a exible shaft as 23a and a rotor as I5 with a flexible shaft as 26a.

As will be vapparent to those skilled in the art, a switch such as the switch 80 may be employed with or without clutches as 82 and 83 and like- Wise clutches as 82 and 83 could be employed with or without a switch as 88, the use of these devices being dictated by the conditions under which my novel apparatus is used.

A further modified form of my invention is shown in Fig. 6 and herein a switch Sb is provided which is similar to the switch S and which includes rotors that in the present instance may be operated at rates proportionate to the rates of rotation of wheels of railway equipment through flexible shafts as 23h and 2Gb that correspond to the shafts 23 and 26.

A source of current Elb is provided and a conductor 48h leads from this source of current to a terminal in the switch Sb corresponding to the terminal 49 in the switch S. Conducminals and 53 in the switch S. The conductor 50h leads to a terminal 91 while the conductor 52b leads to a terminal 88. Three slowtorelease relays SRlb, SRZb and SR3b are provided.`

A conductor 42b leads from the source of currentas the battery Blb to a terminal 43b and a conductor 4Gb leads from `the terminal 43b to one end of the winding 41b of slowtorelease relay SRIb, a conductor 89connecting the other end of this winding to the terminal 81. A conductor 9U leads from terminal 43h to a terminal 9| and a conductor 44b leads from the terminal 9| to one end ofthe winding 45b of the slow-torelease relay SRZb, a conductor 92 leading from the other end of this winding to `the terminal 88. A conductor |32 interconnects the armature 31b with the terminal 88. the contact 361) to a terminal 94. A conductor 95 interconnects the armature 4Gb with the terminal 81 while a conductor 96 interconnects the contact 39b with the terminal 94. A conductor 1llb leads from the terminal 94 to one end of the winding 91h of the slowtorelease relay SR3b and a conductor Iilb` leads from the other end of this winding to the terminal 9|. The armature 1lb of` the relay SR3b is grounded asindicated at 12b while the contact 13b is connected through a conductor 19h to one end of the winding 1Gb of a solenoid 14b, the `other end of this Winding being connected through a conductor 11b to a source of current as the battery B3b which is grounded as at 18b.

So long as the slowtorelease relays SRlb, SRZb and SR3b are operative the armatures 31b, 40h and 1lb are respectively engaged with the contacts 36h, 39h and 13b.

In the switch Sb there is a brush similar to the brush 64 and contact strips similar to the contact strips 69 and 6|. When this brush engages a contact strip similar to the contact strip 60 circuit is closed from the conductor48b to the conductor 50b and when this brush engages a Contact strip similar to the contact strip 6| circuitY is closed from the conductor 48h to the conductor 52b.

When circuit is closed from the source of current as the battery Blb through conductor 49b, switch Sb, conductor 50h to terminalN 81, and through conductor B9, winding 41b and conductors 46h and 42b back to the source of current Blb, the slowtorelease relay SRIb is energized and the armature 31h thereof is engaged with the contact-36h. In normal operation this does not close circuit to the winding 61b since circuit to the conductor 52b is not closed at the same time circuit to the conductor 59b is closed andtherefore the engagement of the armature 31h with the contact 36b does not close circuit from terminal 88 through conductor |32, armature 31b, contact 36h, conductor93 to terminal 94. also closes circuit to'conductor 95, circuit is not closed through armature 40h, contact 39h and conductor 96 to terminal 94 unless relay SRZb is operative to engage armature rl|||b with contact i-l9b.l

When circuit is closed to conductor 52b, it 'is also closed to terminal 88 and in normal operation this does not close circuit throughy conductor |32, armature 31b, contact 36b and conductor 93 to terminal 94 for at this time armature 31b will be disengaged from contact 36h.. However,

closing of Circuit to conductor 5`2b also closes` A conductor 93 leads from While closing of circuit to conductor 59hv circuit to conductor 92 and through winding 45b,

conductors 44b, `9|| and 42b, circuit is closed back to the source of current Blb whereupon the winding 45b of relay SRZb is energized and the armature 40h is engaged with the contact 39h.

In the operation of the device when the brush in the switch Sb -corresponding to 'the brush 64 in the switch S moves from engagement with one contact strip in the switch Sb, similar to the contact strips BI) or 6|, as the case may be, in a period of time such that the slowtorelease relay in circuit with the rst of the so engaged strips is still operative at the time the brush engages the other of the contact strips, circuit will be closed to the terminal 94.

Thus, if the slowtorelease relay SRIb were the first `of the two relays to be energized and is the one which remains operative, then the armature 31b thereof is engaging the contact 36h ywherefore when the brush engages the one of the contact strips that closes circuit to conductor 52b, circuit will be closed from terminal 88 through conductor |32, armature 31b, contact 3Eb and conductor 93 to terminal 94. At this vsame time the winding 45b will be energized ductor 96.

In either event it will be noted that when both the slowtorelease relays SRlb and SR2b are operative circuit is closed to the terminal 94 from wthe source of current Blb through conductor 48b and switch Sb and either through conductor 50h, terminal 81, conductor 95, armature 491), contact 39h and conductor 96 or through conductor 52b, terminal 89, conductor |32, armature 31b, contact 36b and conductor 93. From terminal 94 circuit is closed through conductor 10b, winding 61b and conductors 68b, 9|) and 42b back to the source of current Blb whereupon the slowtorelease relay SR3b is rendered operative to attract its armature 1|b into engagement with the contact 13b whereupon circuit is closed through the winding 1Gb of the solenoid 14b from ground at 12b through armature 1lb, contact13b, conductor 19b, Winding 1Gb and conductor 11b to the source Aof current as the battery B3b and to ground at 18b. This energizes the winding of the solenoid 14b which may be arranged to operate a combined vent and check valve similar to the combined vent and check valve 15, Fig. .5, and thereafter a control operation will proceed in the manner described in connection with the description of Fig. 5.

The arrangement shown in Fig. 6 is quite similar to that shown in Fig. 5 but has an advantage over the arrangement shown in Fig. 5 in that the relay SR3b starts to energize as soon as a brush similar to the brush 64 engages a second contact strip, While the slow-to--releasev relay energized by engagement of the brush with the rst of the strips is still operative, Whereas in the arrangement shown in Fig. 5 it is necessary that the relay in circuit with the second of the strips so engaged be energized before circuit i to slow-to-release relay SR3 is closed. In other respects the arrangements shown in Figs. 5 and 6 operate in an identical manner.

Theform of my invention shown in Fig. 1 may be used either with the arrangement shown in Fig. 5 or the arrangement shown in Fig. 6. If used with the arrangement shown in Fig, 5, the conductor c, Fig. 7, would lead from a contact corresponding to the contact'36a to winding 61e and through conductor 68o and battery B2C to ground at 69C. If used with the arrangement shown in Fig. 6, the conductor 10c would lead from` a terminal correspondingto the terminal 94, Fig. 6, through winding 61e, conductor 68C and the conductor shown in broken lines and indicated by c in Fig. 7 to a terminal corresponding to the terminal 9| and in this instance conductor 08C would not be connected to a source of current as B2C as shown in full lines in Fig. '7. Thus in the arrangement shown in Fig. 7 the slow-to-release relay SRSU is energized whenever an abnormal condition exists and the energization of this relay engages the armature 1Ic with the contact 13C to ground the conductor IOI.

In the present instance the conductor |0I leads to a terminal 91 and when conductor IUI is grounded circuit is closed through a conductor 98, armature 99, contact |00, conductor 19o, winding 160, conductor 11c, through the source of cur-rent B30 to ground at 18C. The winding 10c is part of a solenoid 14e which corresponds to, is for the same purpose as, and operates in the same manner as the solenoids 14 and 14h.

If in the operation of the arrangement shown in Fig. 7 the solenoid 14e is maintained operative for more than a predetermined period of time, then circuit thereto is broken. The predetermined period of time for which the solenoid 14c may continue to be operative will be of sufficient length to'enable an intended control operation to be completed. Such a control operation, as explained above, may be release of braking means or a reductiton in the eiTectiveness of such means. When, however, operation of the solenoid 14C is not interrupted at the end of such predetermined period of time, the control operation should nevertheless be` inter rupted because this will be indicative of an inadvertent and improper condition. To this end a slow-to-energize relay SEI is provided and the aforesaid armature 99 and contact |00 are a part of this relay.

The slow-to-energize relay SEI includes a winding |02, one end of which is connected to the terminal 91 through a conductor |03, the other end of this winding being connected to a source of current as the battery B4 through a conductor |04, said battery being grounded at |05. The slow-to-energize relay SEI isv such that the armature 99 thereof is not attracted from engagement with the contact |00 into engagement with the contact |06 until a predetermined time after circuit to the winding |02 of this relay has been closed by the engagement of armature 1Ic with contact 13C.

Thus when the armature 1Ic is engaged with the contact 13C to apply ground on the winding 1Go and thereby render the solenoid 14e operative, circuit is also closed from ground at 12c through armature 1Ic, contact 13C, conductor IOI, terminal 91 and thence through conductor |03, Winding |02 and conductor |04 to battery Y B4 and ground at |05. This energizes winding |02 but the armature 99 of the relay SEI is not attracted until circuit has been closed through the winding |02 for a predetermined time. When, however, circuit remains closed through the winding |02 for a predeterminedperiod of time, the armature 99 is attracted from engagement with the contact |00 into engagement with the contact |06 and thereupon circuit is closed from ground at |05 through'the source of current B4, conductor |04, winding |02, conductor |03, terminal 91, conductor 98, armature 99, contact |06, conductor |01 to fixed contact |08 and through movable contact |09 to ground at IIO whereby a stick or holding circuit is closed through winding |02 to maintain the relay SEI energized.

Such disengagement of armature 99 from contact |00 breaks circuit to winding 16e wherefore the solenoid 14e is rendered inoperative. The solenoid 14o will remain inoperative and no further control operations will be effected until the stick circuit through winding |02 is broken. This stick circuit can only be broken by manually disengaging the movable contact |09 from the xed contact |08 and this will not be done until the reason why circuit remained closed to the winding 16e for greater than a predetermined period of time has been ascertained. Thus by the arrangement shown in Fig. 7 my device may be rendered inoperative until manually rendered operative and this will occur whenever a control operation is prolonged for greater than a predetermined period of time.

Obviously it will be advantageous to indicate the disengagement of the armature 99 from the contact I 00 and the engagement thereof with the contact |06. Hence the sloW-to-release energize relay SEI is provided with another armature II| that is adapted to engage the contact I|2 simultaneously with the engagement of the armature 99 with the contact |06. The armature III is grounded as indicated at |I3 and a conductor ||4 leads from the contact ||2 to a terminal II5. Thus circuit is closed to terminal II5 each time a stick circuit is closed for relay SEI.

A circuit from ground is closed from the terminal |I5 through conductor II6, a visible signal such as the lamp L and conductor II1 to a source of' current as the battery B5 each time terminal ||5 is grounded by the engagement of armature I I I with contact I I 2, said source of current B5 being grounded at I|8. A conductor II9 leads from the terminal |I5 to an audible signal such as the buzzer N which is connected to a source of current as the battery B6 through a conductor |20, said battery being grounded as indicated at I2 I. Thus the buzzer N is rendered operative each time terminal I I5 is grounded.

Thus the visible signal L and the audible signal N are rendered operative whenever the solenoid 14e is rendered inoperative by the disengagement of the armature 99 from the contact |00. While it may be advantageous to maintain both the audible signal N and the visible signal L operative once circuit thereto is closed, there may be circumstances Where it will be desirable to interrupt circuit to one or the other or both of these signals and to this end a manually operable switchmay be provided for this purpose, such a switch being indicated at |22 and being provided in the conductor I I9 to enable the audible signal N tobe rendered inoperative by the manual opening of this switch. Of course, a similar switch could be provided in the conductor IIB to render the visible signal L inoperative or such a switch could be provided in the conductor II4 so that both of the signals could be ren-A dered inoperative if desired.

The arrangement shown in Fig. 8 is similar to that shown in Fig. 6 except that the arrangement shown in Fig. 8 enables a single source of current to be utilized and a different type of switch is employed.

The switch shown in Fig. 8 includes a shaft |8d suitably journaled in the switch housing (not shown) and this shaft is to be connected to a flexible shaft or the like corresponding to the flexible shaft 26. A shaft |1cl is also provided and which is also to be journaled in suitable bearings in the switch housing and a flexible shaft similar to the flexible shaft 23 is to be connected thereto. The flexible shafts used with the shafts |1d and |8d, Fig. 8, are to be arranged, for example, to cause these shafts to rotate at rates proportionate to the rates of rotation of, and in the same direction as, different wheels of Vrailway equipment or the like, althrough these shafts need not necessarily rotate in the same direction as the wheels.

In this switch a conductive disc |23 is mounted on the shaft |8d but insulated therefrom and stationary spring contacts |24 engage this disc. Conductive discs |25 and |26` are mounted on but insulated from the shaft |101, and stationary contacts |21 and |28 respectively engage the discs |25 and |26. A plate |29 of insulating material is also fast on the shaft |1d and carries contact strips 60d and Bld spaced from each other and of an extent similar to the contact strips 6U and 6|. A spring contact 64d is carried by the bracket |30, fast on the shaft Id, and this spring contact is adapted to successively engage the strips 60d and Bld in a manner similar to that in which the brush 64 engages the contact strips 6U and 6|. The spring contact 64d is connected to the disc |23 through a conductor |3|. The contact strips 60d are connected to the disc |26 through a conductor 62d while the contact strips Gld are connected to the disc |25 through a conductor 63d.

In use the shafts |1d and |Bd are operated at rates proportionate to the rates of rotation of different wheels on railway equipment or the like and so long as the relative rotation between these shafts is such that the spring contacts 64d do not disengage one of the contact strips 60d or 6 Id and engage the other of the contact strips in a time equal to or less than the release time of the slow-torelease relays SRId and SE2d, the slowto-release relays SRId and SE2d are not operative simultaneously, closed to the slow-to-release relay SR3d. When however, the spring contact 64d disengages one contact strip 60d or Gld and engages the other contact strip prior to the release of the slow-torelease relay energized by the engagement of the spring contact with the first of such strips, then circuit is closed to the slow-to-release relay SRSd.

Assuming that the spring contact 64d is engaging contact strip Ell, as shown in Fig. 8, then circuit is closed from the source of current Bld through conductor |34 to terminal |33 and from there through conductor 48d to spring contact |24 and thence through disc |23, conductor |3|, spring contact 64d, contact strips 60d, conductor 62d, disc |26, spring contacts |28 and conductor 50d to terminal 81d. From terminal 81d circuit is closed through conductor 89d, Winding 41d and conductors 46d and 42d`back to the source of current Bld whereupon slowto-release relay SRld is rendered operative to engage the armature 31d thereof with contact 36d. This however does not close circuit to the winding wherefore circuit is noty 61d of slow-to-release relay SR3d since circuit to conductor 52d is not closed at this time. Circuit is also closed from terminal 81d through conductor 95d to armature 40d which however at this time is disengaged from contact 39d wherefore circuit is not closed to the winding 61d.

If, however, the spring contact 64d moves from` engagement with the contact strip 60d into engagement with the contact strip Bld prior to the time slow-to-release relay SRId has released its armature 31d, then circuit is closed from the source of current Bld through conductors |34 and 48d, spring contact |24, disc |23, conductor |3|, spring contact 64d, contact strip 6|d, conductor 83d, disc |25, spring contacts |21 and conductor 52d to terminal 88d. From terminal 88d circuit is closed through conductor |32d, armature 31d, contact 36d, conductor 93d to terminal 94d. Circuit is also closed at this time from terminal 88d through conductor 92d, winding 45d and conductors 44d, 90d and 42d back to the source of current Bld wherefore the winding 45d of relay SRZd is energized. If, therefore, the spring contact 64d moves from engagement with the contact strip 6|d into engagement with the contact strip 60d prior to the time relay SE2d has released its armature 40d, circuit will be closed from terminal 81d (to which circuit will be closed y in the manner above described) through conductor 95d, armature 48d, contact 39d and conductor 96d to terminal 94d.

In either event when circuit is closed to terminal 94d, winding 61d is energized, current iiowing from terminal 94d, through conductor 10d, winding 51d and conductors 68d, |35, Sd and 42d back to the source of current Bld whereupon slow-to-release relay SR3d is energized.

Slow-to-release relay SR3d. is similar to and operates in the same manner as slow-to-release relay SR3 and when energized attracts its armature 1 Id into engagement with contact 13d whereupon circuit is closed from the course of current Bld through conductor |34, terminal |33, conductor 12d, armature 1|d, contact 13d, conductor 11d, winding 16d and conductors 19d, |35, 80d and 42d back to the source of current Bld. This renders solenoid 14d operative and this solenoid operates in the manner above described with ref- @rence to solenoid 14 to operate a valve similar to the valve 15 for the purpose and in the manner above described.

A modification of the form of the invention shown in Fig. 8 is illustrated in Fig. 10, the difference between Figs. 8 and 10 residing in the form of switch employed.

In the form of the invention shown in Fig. 10 shafts |1e and |8e are suitably journaled in bearings in the switch housing (not shown) and flexible shafts, corresponding to the flexible shafts 23 and 26, are connectedto the shafts |1e and |86 so that they may be rotated at rates proportionate to the rates of rotation of, and in the same direction as, the wheels of railway equipment or the like although, here again, the shafts need not rotate in the same direction as the wheels. The shaft |8e however carries a substantially cupshaped member |3|le of insulating material and contact strips 60e and Ble are mounted on the inner periphery of the member |30e, said stripsy being of a length similar to and being spaced similarly to the contact strips 60 and 5| in the switch S. A conductor|i3e connects the strip Ble with a disc |256, similar to the disc |25 and on which the brush |21e bears. A conductor 62e interconnects the strip 60e with a disc |26c, similar to the disc |26 and on which the brush |28e bears. An annular body |296, fast on the shaft l1e, is disposed within the substantially cup-shaped mem-v ber-|e and carries a brush 64e that is urged outwardly by a spring |36 so that the brush will successively ride over the contact strips 60e and 6 le upon relative rotation between the shafts |1e and Ille. A conductor |3le interconnects the brush 64e with the disc l23e similar to the disc |23, and on which the brush l24e bears.

The switch shown in Fig. 10 operates in a manner similar to that hereintofore described and could be used in place of any of the switches thus far described. If this were done, for example in so far as Fig. 8 is concerned, the conductor 48e would lead to a terminal similar to the terminal |33,v Fig. 8, while the conductors 50e and 52e would respectively lead to terminals corresponding to the terminals 81d and 88d, Fig. 8. It is obvious that with the switch shown in Fig. 10 connected in this manner it would operate similarly to the switch shown in Fig. 8 to bring about a control operation in the above described manner.

A further modified form of my invention is shown in Fig. 11 and herein a somewhat different circuit and a somewhat different switch are illustrated. The circuit shown could be used with any of the switches thus far described and the switch shown herein could be used with any of the circuits thus far described. In the form of my invention shown in Fig. 11, shafts |1f and If are provided which in the manner previously described may be connected to the wheels `of railway equipment to rotate at rates proportionate to the rates of rotation of such wheels and in the same direction, if desired.

A cam member |38 is slidably but non-.rotatably mounted on the shaft |8f while a cam member |39 is fast on the shaft l1f. The cam members |38 and |39 have complementary cam surfaces |40 and |4| and a spring |42, disposed about the shaft 8f between the cam member |38 and the collar |43 fast on this shaft, urges the cam surfaces |40 and l4| into cooperating relation. When the cam surfaces are cooperating with each other in the manner shown in Fig. 1l the cam member |33 permits the rider |31 to assume the position shown wherein the contact |i4f, controlled by the rider |31, engages the contact 60f. However, if the cam surfaces move relative to each other so that the high portions of the cam surface |40 are opposite the high portions of the cam surface |4l, then the cam member |38 engages the rider |31 and moves the contact 64f from engagement with the Contact 60) into engagement with the contact Elf.

Assuming that the shafts 1f and |8f have been rotating at substantially the same rate and that the cam surfaces |40 and |4| are cooperating with each other in the manner shown in Fig. 11, then the contact B4f engages the contact |i0f and circuit is closed from the source of current Blf through conductor |34f, terminal |33f, conductor 48j, Contact 64f, contact 60f, conductor f, to armature 40f which at this time will be disengaged from contact 39f and hence circuit is not closed in this instance to any of the slow-to-release relays SRI f, SR2 f or SR3f.

When, however, the high portions of the cam surfaces |40 and |4| are cooperating with each other, circuit is closed from the source of current Blf through conductor |34f, terminal |33f, conductor 48f, contact 64j, contact Blf, conductor 52j to terminal 88f and from terminal 88f through conductor 92j and .winding 45j, back through conductors 44f and 42j to the source of current Blf whereupon slow-to-release relay SRZf is energized and the armature 40f is engaged with the contact 391. This however does not close circuit to the winding 41f if the high portions of the cam surfaces |40 and l4| are still opposite each other.

If, however, the relative rotation between the shafts |1f and lsf is such that immediately after the high portions of the cam surfaces |40 and |4| have been aligned with each other the cam surfaces move into relationship shown in Fig. 1l, then the Contact 64f engages the contact 60f and thereupon circuit is closed from the source of current Blf through conductor |34f, terminal |33f, conductor 48f, contact 64j, contact 60j, conductor 50f to armature 40f. If the contact 4f engaged the contact @0f prior to the time the slow-to-release relay SR2f has released the armature 40f from the contact 39f, then circuit is closed through conductor 66], winding 41j, and conductors 46f, 90f and 42f back to the source of current Blf whereupon slow-to-release relay SRlf is energized and armature 31f thereof is engaged with contact 36j.

Hence if the relative rotation between the shafts |1f and IBf continues and the high portions of the cam surfaces |40 and |4| move in to alignment with each other prior to the time the slow-to-release relay SRlf has released armature 31j from contact 36f, then circuit is closed to terminal 88)e in the manner above described and from terminal 38) through conductor |32f, armature 31f, contact 36f, conductor 10j, winding 61f, and conductors 6||f, |35f, 001 and 42f backv to the source of current Blf whereupon slow-to-release relay SR3f energizes.

It will be apparent from the foregoing description that the arrangement shown in Fig. 1l requires the successive engagement of two slowto-release relays in less time than the release times of such slow-toerelease relays in order that the slow-to-release relay SRSf will be operative. Hence this arrangement requires that the need for a control operation be prevalent for a greater period of time than any heretofore described. When, however, the slow-to-release relay SR3f is energized it operates in a manner similar to that described with reference to the slow-torelease relay SH3, Fig. 5, and the solenoid 14f is rendered operative to operate a valve similar to the valve 15, Fig. 5, or to bring about any other desired control operation, circuit being Y closed to the winding 16f of the solenoid 14j so long as slow-to-release relay SR3f is operative from the source of current Blf through conductor |34f, terminal |3-3f, conductor 12f, armature 1| f, contact 13f, conductor 11f, winding 1li]c and back through conductors 19f, |35f, 00f and 42f to the source of current Blf..

A still further modified form of switch is shown in 1nig. 13A and herein shafts |1g and Ig are provided which are adapted to be operated at rates proportionate to the rates of rotation of wheels of railway equipment or other rotative devices to be controlled, and hence these shafts are similar to corresponding shafts previously described. Three discs |23g, |259 and |269 are mounted on the shaft -lg to rotate therewith but these discs are linsulated from this shaft. Brushes |249, l21g and l28g respectively bear on these discs and conductors 48g, 52g and 50g are respectively connected to these brushes. These |1h as shown in Fig. 13.

conductors correspond to the conductors hereinabove described and numbered 48, 52 and 50, both with and without suffixes. Contact strips 60g and Ely are carried by the shaft |8g as are flexible plates |29g and |289. strip 6|g is connected to the disc |25g by a lconductor 63g, the contact strip 60g is connected to the disc |26g by a conductor 62g, while the flexible plates |299 and |299' are connected to the disc |23g by a conductor |3|g. A plate |45 is fast on the shaft |1g and carries a pair of rollers |46 and |41, of Whichroller |46 is successively engageable with plungers |48 and |49 in the disc |50 that is fast on the shaft |89. The roller |41 is a balance roller to avoid unnecessary vibration in the device.

When the shafts |1g and |8g rotate relative to each other the roller |46 so successively engages the plungers |48 and |49 and forces these plungers inwardly that first the flexible plate |29g is engaged with contact strip 60g and then the plate |29g is engaged with the contact strip The contact Slg. When this successive engagement of these flexible plates with the contact strips 60g and 6 g is such that the engagement occurs at intervals of time equal to or less than the release time of slow-to-release relays in circuit with the conductors 52g and 50g, as above described in connection with conductors numbered 48, 52 and 50, both with and without suflixes, then operation of a solenoid such as the solenoid 14j (or the solenoids 3| and 33) is brought about for the purpose hereinabove described, for it will be recognized that the engagement of the flexible, plate |2957 with the contact strip 60g closes circuit from conductor 48g to conductor 50g while engagement of the flexible plate |29g with the contact n strip 6|g closes circuit from conductor 48g to conductor 52g.

The arrangement shown in Fig. 13 differs from that hereinabove described inasmuch as only one slow-to-release relay is employed to determine whether or not a control operation is to be instituted. Furthermore, a somewhat different type of switch is illustrated in Fig. 13.

The switch shown in Fig. 13 includes shafts |171. and |871. similar to shafts |1 and I8 and which are operated similarly to said shafts `|1 and I8. A cam member |3871V is fast on the shaft |871. while a disc |3971 is fast on the shaft |171.. The cam member |3871. embodies a cam surface |4071. including high and low portions. A rocker |5| is pivotally mounted at |52 on the disc |3971. and includes a rider |53 that is urged into engagement with the cam surface |40h by the action of a spring |54 on a plunger |55, said spring and plunger being mounted in the shaft A guide |56 is mounted on the disc |3871. to insure proper rotation of the rocker |5| `with the disc |3971.. The plunger |55 includes a stem |51 on which the rider |3171.

bears.

'j am.

In the switches shown in Figs. 11 and 13, the contacts 641 and 6471. may remain in engagement with one or the other of their two cooperating contacts for relatively protracted periods in normal operationof the device but of course when there is relative rotation between the shafts and the members mounted on these shafts, the contacts 64j and 6471. move from engagement with one ycooperating contact into engagement with the other cooperating contact in a relatively rapid manner for when there is appreciable `relative rotation between the shafts as |1J and IB it is indicative, in the present instance, of a wheel sliding condition and therefore a control operation is to be initiated. .Of course, due to sharpness of the inclination between the two different cam surface levels of a device shown in Fig. 13, the shift of contact 6471. from either contact 6071. or 6|7L to the other will occur more rapidly than in the arrangement shown in Fig. 11 for the same difference in the rates of rotation between the shafts. Furthermore, it is intended that by reason of such sharpness of inclination between the cam surfaces the contact 6471. will move from either contact 60h or' Elh to the other, or vice versa, in such time that there will be little if any interval between such engagements.

In normal operation so long as the contact 6471. remains in engagement with the contact 60h circuit is closed from the source of battery Blh through conductor |3471, terminal |3371., conductor 48h, contact 6471., contact 60h, conductor 5071. to terminal 8171.. This closes circuit to conductor |58 and winding |59 of slow-to-energize relay SEZ for this complete circuit back to the battery Blh. through conductor |60, terminal IBI, conductor |62, terminal |63 and conductor 4271.. Relay SEZ being a slow-to-energize relay may therefore energize in normal operation to attract its armature |64 from normal engagement with the contact |65 but this is Without effect in normal operation.` Furthermore, when circuit is closed to terminal 8171. circuit is also closed to conductor |68 and terminal |68. From terminal |69 circuit is then closed through conductor 9571. to armature |66 which remains disengaged from contact |61 until relay RI is energized. Closing of circuit to terminal |69 closes circuit through conductor |10, winding |1| of slow-to-release relay SRA, conductor |12, terminal |13, conductor |14, terminal 6|, conductor |62, terminal |63 and conductor 4271. back to the source of current Blh. This energizes slow-torelease relay SR4 whereupon the armature |15 thereof is attracted into engagement with contact |16. In normal operation the engagement of armature |15 with contact |16 is without effect since circuit will not be closed from source of current Blh through conductor |3471., terminal |3371., conductor 4871., contact 6471., contact 6|7z. and conductor 5271. to armature |15 and hence relay RI is not energized, assuming shafts I1h and |8h are rotating at equal rates.

It has been explained hereinabove that contact 64h is rapidly disengaged from contact 6071. and is almost instantaneouslyl moved into engagement with contact 6|71. whenever the rider |53 moves from the high portion of the cam surface |4071 and onto the low portion thereof. It has also been stated that in normal operation there is apt to be a slight difference in the rates of rotation of the wheels to which the rotating elements as |3871. and |3971. of the switch vassembly are respectively connected, due, for example, to a discrepancy in diameters of these wheels. Therefore, it may happen that in normal operation the contact 6471. will become disengaged from contact 6071. and will move into engagement with contact 6|71. before the slowback to the source of current Blh, whereupon f relay RI is energized.

The slow-to-relea'se relay SR4 also includes an varmature l|82 which remains in engagement with the contact |83 so long as the armature |15 remains in engagement with the contact |16.

Hence at the time circuit is close-d through the Winding |89 'of relay RI, circuit is 'alsoclosed from` battery Blh through conductor |3411., terminal |33h, conductor |84, terminal |85, kconductor |86, armature |82, contact |83, conductor |81, armature |64 and contact |65, inasmuch as slow-to-energize relay S1312 is not energized at this time, and through conductor |98 to terminal |89. Since at this time relay RI is jenergized, circuit isrnow closed from terminal |89,

through conductor |98, contact |9|, armature |92 0I relay RI through conductor '|93 to terminal |18 whereupon a stick or holding circuit for relay RI is established.

As will be shown more fully hereinafter, the 5" 'energi'zation of relay RI is without effect upon the remainder of the apparatus unless yslow-torelease relay SR4 maintains its armatures |15 and |82` in engagement with ytheir 'respective contacts |16 and |93 throughou'tthe 'entire interval between two successive engagements o'f the contact 64h with contact 60h. During normal op- `eration this interval is "always greater than the deener'gization time 'of the relay SR4, so that relay RI will be dee'nergized, as a result di the 'disengagement o'f armatures |15 and |82 from their respective Acontacts upon 'deenergization of `relay SRI, prior to the time contact 'sah again engages contact 68h. Hne,during normal opera- 'tion the armature |66 Yof relay R] will be disengaged from its contact |61 at all times when Vcontacts '60h and 64h are in engagement with veach other, and therefore circuit is Vnot completed beyond armature |66.

h However, when Aanl abnormal vcondition arises and the shafts |1h and |611, start to rotate relaltive to eachother at such a rate that after the contact -6th, hasen'g'ag'ed the contact6 Il), and energized the relay RI the contact 64h is caused to engage the contact l|i|lh-prio1fto the time the' slow-to-release relay SR4 has released its armatures and |82, then circuit is closed 'from conductor |68, terminal |69, conductor 95h, armature |66 of relay RI, which relay will be held energizedy by the above Ltraced stick circuit,

and contact |61, conductor |94, terminal |95, conductor |96, winding |91 of relay R2, conductor |98, terminal |99, conductor 298, terminal |63 and conductor 4211I back to the battery BI, whereupon relay vR2 is energized. Furthermore, circuit is closed from the source ofncurrent Blh through conductor |3471, terminal |33h, conductor 48h, Contact 64h, contact 6|llt, anc1 con- 'ductor 50h 'to terminal l81h to again initiate 'en- 'ergiz'ation ofy slow-to-releasere'lay SE2 through rconductor |58 as above described.

The above described lenergization of relay :R2 closes a stick o'r holding 'circuit`V therefor from terminal "|89 through conductor I28|,"contact 202,

`Aarma-ture 2'03 of relay R2 which will beengaged with contact 202, upon energization of said `relay R2, and through conductor 2784 to terminal |95. Hence, so long as slow-'to-energize relay VSZ does not attract its armature |64 and 'so' long as slow-to-'release relay does not release its armature |82, the relays Rl and R2 will beI held energized. However, upon the energization of slow-to-energize relay SEZ or the release of armature |5872 of sloW-toJelease relay SRM, at the end of a period of operation of this relay, the stick circuits for the relays RI and R2 are broken and thereupon' these relays release.

vSo long as the relay R2 reinains energized the armature 1|h thereof is held in engagement with the contact 13h whereupon circuit is' closed through conductor 11h, winding 16h, conductor 19h, terminal |99, conductor 288, terminal |63 'and conductor 42h back to the source of current BH1, wherefore the winding 16h is energized to render the solenoid 1411 opera-tive. Solenoid 14h is similar to solencids heretofore described bear- Ving this reference character with or without -suiixes and therefore energi'zation 4of. the winding 16h brings about a control operati-Unas above described. y v l In Figs. 9 and 12 I have illustrated arrangements wherein switches such asthose which have been thus far described may be supplemented by means for generating an electromotive 'force upon relative rotation of wheels "of railway equipment or the like, such as the relative rotation between such wheels as causes 'operation of the' switches described above. l

Thus inl Fig, 9 I vshow shafts |11' and |91'. A bracket '|381' is provided on the shaft 3i and carries neld pieces FI andFZ, and an armature A is fast on thevshaft '|11' for cooperation with the riem pieces Fl and F2. rn Fig. 12 r have eiagrammatically illustrated an armature A1' and brushes 2|'37` and ZIM. It will be apparent that upon rotation ofthe shafts |11 and lli relative to each 'other that the field pieces F| 'and F2 'will 'rotate relative to the 'armature A 'whereupon electromotiye force will 'be set up in the 'arma- 1 ture A. Upon similar 'relative movement 'between the ar'm'ature Aj and field pieces corresponding to the field :pieces Fl and F'z, Fig. 9, an electromotive 'force will be generated in the 'armature Ay'.

, Referring first to the form "of the .invention shown in Ftg. 9, :a switch similar to that shown in Fig. 8 is employed, said Vswitch omprising the plate |291' o'fA insulating material o'n Iwhich 'contact strips B'Di and [iii Siniil'ar to 'the Contact strips 60d and '6|d`, Fig. '8, are 'provided to be successively engaged with lthe spring contact '6"41'. Then in the manner described with reference to Fig. 8, circuit is alternately closed `from the conductor 481' to the conducto-rs 1561' or '5.21'.

Either in the yman-ner disclosed in Fig. Ai3 or in any other suitable way, the conductors 4813, `i Vand y521' will .be connected in circuit with devices which will bring about operation of a slow-torelase relay SRf'3i, the 'slow-'to-'release "relay SR31`, for example, corresponding to 'the 'slow-torelease 'relay Saad, Fig. s. "ro ruft-,her 'illustrate ho'w the Aslow-to-'release relay SR31' could be ylila'ceiti under control of circuits of which 4the conductors 481', 591' and 521' are a part, conductors 101' and 681' are shown connected yt0 opposite ends of `the winding 611' of the *slow-to-irelease `relay S3312 ySuch conductors 1391' and 681' could 'jlead respectively to Tterr'ninals as `-'Silfl Iand '265, Fig. 8.

contact 2|4 bears on the disc` 2|2.

When circuit is closed through the winding 611' to energize the slow-to-release relay SR31 the armature 1|1' is attracted into engagement with the contact 131' whereupon circuit is closed from a source of current as the battery B31' through conductor 181, terminal 206, conductor 121', armature 1|1'contact 131', conductor 191', terminal 201, conductor 208, winding 161' and conductor 11i back to the battery B31' whereupon the solenoid 14i of which the winding 161' is a part is rendered operative to bring about a control operation such as, for example, that brought about upon energization of the solenoid 14d described above.

It will be recognized that energization of the sloW-to-release relay SR3i is brought about by rotation of the shafts |11' and |81' relative to each other, for example, as relative rotation of the shafts |1d and Id, Fig. 8, brings about energization of the slow-to-release relay SRSd. When such relative rotation between the shafts |11' and |81' occurs there is relative rotation between the eld pieces FI and F2 and` the armature A whereupon an electromotive force is set up in the armature A. Aconduotor 209 leads from` one end of the winding of the armature A to a conductor disc 2|0 mounted on, but insulated from, the shaft |11' while another conductor 2|| leads from the other end of said winding to a conductive disc 2|2 mounted on, but insulated from, the shaft |11'. A stationary spring contact 2|3 bears on the disc 2|0 and another stationary spring A conductor 2|5 leads from the spring contact 2|3 to one end of the winding 2|6 of a relay R3 while a conductor 2|1 leads from the other end of the winding 2 I6 to the spring contact 2|4.

Thus an electromotive force set up in `the armature A is impressed on the winding 2|6 and when this electromotive force is of sufficient magnitude, which would be directly proportionate to the magnitude of the relative rotation between the shafts |11' and |81', relay R3 is energized whereupon the armature 2|8 thereof is attracted into engagement with the contact 2|9 and thereupon circuit is closed from the source of current as the battery B31' through conductor 181', terminal 205, conductor 220, armature 2|8, contact 2|9, conductor 22|, terminal 201, conductor 208, winding 161', conductor 111', and back to .the battery B31' which affords another source of energization for the solenoid 141'.

It will beapparent, so long as the relative rotation between the shafts |11' and |81' is great enough to generate an electromotive force suicient toeifect operation of the relay R3 that circuit` will be closed through the winding 161'. wherefore the solenoid 14i will be maintained operative for the purpose above described.

The arrangement including the relay R3 need notvbe, but could be, as sensitive, or even more sensitive, than that including the slow-to-release relay SR31' but preferably is not as sensitive so that once the relay R3 is rendered operative it will bring about and maintain a control operation, such as is brought about by operation of ,i the solenoid 14i, so long as an abnormal condition, indicated by rotation of the shafts |11' and |81' relative to each other, is prevalent. Of course, when the relative rotation between the shafts |11' and |81' is so reduced that the electromotive force set up is not suiicient to maintain the relay R3 energized, the relay releases and the stick circuit for the winding 161' closed by l vengagement of the armature 2|8 with the contact 2|9 will be broken. Either before or after 75 this, depending upon conditions, the slow-to-release relay SR31' will release freeing the armature 1|1` from the contact 131' whereupon the circuit closed by engagement of said armature with said contact is opened. If desired, a slow-torelease relay could be used in place of the relay R3.

From the foregoing it will be apparent that the arrangement shown in Fig. 9 is such that a dual source of energization for the winding 161 of the solenoid 141' is provided and hence if one or the other of the means controlling this dual source of energization should fail to operate as intended the other may be relied upon to bring about a control operation.

InFig. 12 a modification of the arrangement shown in Fig. 9 is illustrated and herein a conductor 2|1J' leads from the brush 2|37' to one end of the winding 2|67' of the relay R31 while a conductor 2|57' leads from the other end of this winding to the brush 2|47'. It will be understood that the field pieces of the generator shown in Fig. 12 are arranged for rotation at a speed proportionate to the'rate of rotation of a wheel of railway equipment or the like While the armature A7 is arranged for rotation at a rate proportionate to another such wheel and that when the relative rotation between these field pieces and the armature A7' is surlicient to generate an electromotive force that will cause operationo-f the relay R37', the armature 2|87' of this relay is attracted into engagement with the contact 2|07'. Thereupon circuit is closed from ground at 222 through armature 2|87`, contact 2|97', conductor 223, terminal 224 and conductor 225 and through winding 167' and conductor 117' to the source of current as the battery B37' which is grounded as indicated at 187'. The winding 167' is part of a solenoid 147' similar, for example, to the solenoid 14j. The winding 157' has another source of energization which is from ground at 127' through armature 1|7` when it is engaged with contact 137' and thence through conductor 197', terminal 224, conductor 225 and circuit is thereupon closed through winding 167', conductor 117', battery B37' to ground at 187'.

The armature 1|7' is part of a slow-to-release relay SR37', the winding 617' of which is energized from ground at 697' through a source of current as the battery B27' and conductor 687', which is connected to one end of the winding 617'. A conductor i is connected to the other end of the winding 617' and may, for example, be led to a suitable point such as the contact 38a, Fig. 5, so that when a ground connection is made to the contact as 36a in the manner described hereinabove the relay SR37' will be energized.

As in the case of the arrangement shown in Fig. 9, the means for generating an electromotive force is intended to supplement the action of a switch which would cause ground to be applied on the winding 617' when an abnormal condition such aspredetermined relative rotation between the Wheels of railway equipment exists. The two sources of energization for the winding 167' of the solenoid 147' can be used to supplement each otherbut of course one or the other of such sources of energization could be used alone if so desired.

There may be instances Where it will be desirable to render devices under control of switches as S` inoperative as where on railway equipment it is desired to make an emergency stop in such circumstances that it is immaterial whether or 

